1. Field of the Invention
The disclosures herein generally relate to an oxide semiconductor, coating liquid, a method of forming an oxide semiconductor film, a semiconductor element, a display element, an image display device, and an image display system.
2. Description of the Related Art
Energetic promotion of research and development toward practical use of oxide semiconductors in the world has been triggered by the publication of information about an InGaZnO4 (a-IGZO) thin film transistor (TFT) exhibiting mobility that is greater than or equal to that of a-Si in an amorphous state.
However, most of the oxide semiconductors are n-type oxide semiconductors in which carriers are electrons.
When p-type oxide semiconductors comparable to n-type oxide semiconductors become available, by combining the p-type oxide semiconductors with the n-type oxide semiconductors to form p-n junctions, diodes, optical sensors, photovoltaic cells, LEDs, bipolar transistors and the like are enabled. Furthermore, CMOS circuits in which n-type TFT and p-type TFT are combined can be fabricated. Because oxide semiconductors can be made with wide gaps, the above-described devices can be made transparent. Moreover, oxide semiconductors can be applied to active-matrix displays.
The p-type oxide semiconductors are known to include, for example, Cu2O, CuAlO2, CuInO2, SrCu2O2, and SnO (see, for example, Japanese Unexamined Patent Application Publications No. H11-278834, No. 2000-150861, and No. 2005-183984, and Nature, Vol. 389, pp. 939-942 (1997)).
Moreover, the bipolar oxide semiconductors are known to include, for example, CuInO2 (see, for example, Applied Physics Letters, Vol. 78, pp. 1583-1585 (2001)).